1. Field of the Invention
This invention relates to a roller for electrophotography which is used as a charging roller or the like in electrophotographic apparatus, and a process for its production.
2. Description of the Related Art
A charging roller of a contact charging assembly is so disposed as to be kept in contact with an electrophotographic photosensitive member (hereinafter called “photosensitive member”; at a stated pressing force by a pressing means such as springs provided on both sides of the former's shaft, and be followingly rotated as the photosensitive member is rotated. As such a charging roller, in order to improve the uniformity of images, a charging roller on the surface of which an unevenness of about few μm has been formed is known in the art.
Japanese Patent Application Laid-open No. 2007-225914 discloses a charging roller having art electrically conductive support, a resistance control layer and a surface coat, where roughened-surface forming particles are exposed to the surface of the surface coat so as to form the unevenness. In such a charging roller, the state of exposure of the particles to the surface is controlled to achieve a superior charging performance. Also, in such a charging roller, its contact with the photosensitive member stands multiple-point contact basically, and hence the coefficient of dynamic friction lowers to bring an effect that toners, external additives, paper dust and so forth can be kept from sticking to its surface.